America’s richest families may be giving less to charity, but they are giving more of their time to causes that need their help, a new study finds.

Last year, 95 percent of households that earned more than $200,000 donated money to at least one charity, according to the 2012 Bank of America Study of High Net Worth Philanthropy. But the amount affluent families gave to charity has fallen 7 percent in the past three years.

The average amount donated by high net worth households dropped to $52,770 last year from $56,621 in 2009.

While the wealthy are forking over less cold, hard cash, they’re making volunteering more of a priority. In 2011, 89 percent of high net worth individuals gave their time to a cause, up 10 percentage points from 2009. Over one-third of these do-gooders volunteered more than 200 hours.

When it came to choosing an organization for donations, wealthy donors said they felt most motivated by “how a gift can make a difference” and were most inclined to give to religious and educational organizations, the study found.

“Satisfaction relates to the perception that these donors have about the outcomes and effects of their charitable activity," the study notes, "while fulfillment relates to the feelings that their activity engenders.”

Click through the slideshow below to see which billionaires have pledged to give half of their fortunes away:

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  • George Lucas

    Hollywood director George Lucas is passionate about education. He has worked to foster positive growth in the education sector through, <a href="http://www.edutopia.org/" target="_hplink">Edutopia</a>, the George Lucas Education Foundation. Lucas plans to donate the majority of his fortune to this end.

  • Paul G. Allen

    Microsoft co-founder Paul Allen has supported his namesake, the <a href="http://www.pgafoundations.com/" target="_hplink">Paul G. Allen Family Foundation</a>, for more than 20 years, as well as helped advance nonprofit scientific research through the Allen Institute for Brain Science. Allen has already given hundreds of millions of dollars to charity through his foundation, and has expressed his commitment to give the <a href="http://www.huffingtonpost.com/2010/07/15/paul-allens-charity-promi_n_648142.html" target="_hplink">majority of his fortune</a> after his death.

  • David Rockefeller

    The Rockefeller family has historically been involved in philanthropic efforts supporting University of Chicago, <a href="http://www.rockefeller.edu/" target="_hplink">The Rockefeller University</a>, the Museum of Modern Art, and the <a href="http://www.rbf.org/" target="_hplink">Rockefeller Brothers Fund</a>. David Rockfeller, the current heir, has pledged the majority of his wealth to charity.

  • Michael Bloomberg

    Mayor of New York City Michael R. Bloomberg plans to give away the majority of his wealth during his lifetime, explaining that it is a better way to ensure a <a href="http://givingpledge.org/#michael+r.+_bloomberg" target="_hplink">better future for his children</a> than leaving them to inherit his fortune. According to Bloomberg, his <a href="http://www.mikebloomberg.com/index.cfm?objectid=B96D19BD-C29C-7CA2-F72C5EDC3BEDFA6A" target="_hplink">foundation</a> is currently working to find ways to prevent early deaths caused by tobacco use and traffic accidents.

  • Barron Hilton

    Barron Hilton (left) plans to immediately pledge over $1 billion to the <a href="http://www.hiltonfoundation.org/" target="_hplink">Conrad N. Hilton Foundation</a>, which provides funds for nonprofits addressing a variety of issues, including homelessness, access to clean water and disaster relief. Hilton also plans to follow an example set for him by his father, donating the remaining 97 percent of his wealth in the future.

  • Jon and Karen Huntsman

    After losing his mother to cancer, businessman Jon Huntsman felt called to found the <a href="http://www.hci.utah.edu/" target="_hplink">Huntsman Cancer Institute</a> and use his fortune to find a cure for cancer. Huntsman plans to leave his entire estate to his foundation and other cancer-related charities.

  • Ted Turner

    In 1998, media mogul Ted Turner donated $1 billion to start the <a href="http://www.unfoundation.org/about-unf/" target="_hplink">United Nations Foundation</a>. Turner plans to continue giving, saying that his fortune should be almost completely distributed to charity at the time of his death.

  • Alfred Mann

    In 1985, businessman Alfred Mann founded the <a href="http://www.aemf.org/" target="_hplink">Alfred Mann Foundation</a> to fund scientific research in the field of medicine. Mann has joined the ranks of the 'Giving Pledge,' planning to commit 90 percent of his estate to his foundation and other causes.

  • Eli and Edythe Broad

    Billionaire businessman and real estate mogul Eli Broad and his wife, Edythe, have pledged to give away 75 percent of their fortune within their lifetimes. The <a href="http://www.broadfoundation.org/" target="_hplink">Broad Foundation</a> supports arts organizations, funds advancements in medical science and advocates for education reform.

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